Apple’s iTunes store still dominated U.S. online movie market in the first half of 2011, followed by Microsoft’s Zune Video Marketplace, while Wal-Mart’s Vudu movie service beat Sony’s PlayStation Store and Amazon’s digital movie offering, according to the new research by IHS, CNET reported.

As part of the Screen Digest Media Research program, the study found that iTunes saw its first market share increase since 2009, from 64.9 percent of the market in 2010, to 65.8 percent in 2011.

“Much of iTunes’ success can be traced to the rising usage of Apple’s AirPlay system, which allows wireless video streaming to consumer electronic devices including televisions,” according to Arash Amel, research director, digital media, for IHS in a statement.

“This has expanded the reach of iTunes to new platforms, boosting sales of movies from the system.”

Vudu boosted from just 1 percent market share to 5.3 percent year-over-year, while Amazon only increased slightly from 4 percent to 4.2 percent this year.

Microsoft’s Zune Video Marketplace dropped from 18.5 percent to 16.2 percent year-over-year, which IHS blames on the cool-down of holiday console sales, which were boosted by Microsoft’s Kinect accessory. As for Sony, the report pointed out that Vudu cannibalized potential Sony sales with its application for PS3, as well as the temporary shut down of Sony’s PlayStation Store following the security breach.